Don't crash if calling a method on a QObject that has been gc()'d

As we don't actually delete an object immediately when it is collected,
it is possible to get into a situation where a method is called on an
object after the collector has marked it to be destroyed.  This fixes
a crash in this case.

Change-Id: I131d4c5d7ed788a91aa52f6af2e5c089d9bf5e08
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

2 files changed, 30 insertions, 1 deletions

diff --git a/tests/auto/qml/qqmlecmascript/data/deleteLaterObjectMethodCall.qml b/tests/auto/qml/qqmlecmascript/data/deleteLaterObjectMethodCall.qml
new file mode 100644
index 0000000000..d1418e57a1
--- /dev/null
+++ b/tests/auto/qml/qqmlecmascript/data/deleteLaterObjectMethodCall.qml
@@ -0,0 +1,22 @@
+import QtQuick 2.0
+import Qt.test 1.0
+
+QtObject {
+    property var fn
+
+    property var c: Component {
+        MyQmlObject {
+            function go() {
+                try { methodNoArgs(); } catch(e) { }
+            }
+        }
+    }
+
+    Component.onCompleted: {
+        var f = c.createObject().go;
+
+        gc();
+
+        f();
+    }
+}
diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index 5842ab057e..ee9c7ee89d 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -246,7 +246,7 @@ private slots:
     void invokableWithQObjectDerived();
     void realTypePrecision();
     void registeredFlagMethod();
-
+    void deleteLaterObjectMethodCall();
     void automaticSemicolon();
     void unaryExpression();
     void switchStatement();
@@ -6001,6 +6001,13 @@ void tst_qqmlecmascript::dynamicString()
              QString::fromLatin1("string:Hello World false:0 true:1 uint32:100 int32:-100 double:3.14159 date:2011-02-11 05::30:50!"));
 }
 
+void tst_qqmlecmascript::deleteLaterObjectMethodCall()
+{
+    QQmlComponent component(&engine, testFileUrl("deleteLaterObjectMethodCall.qml"));
+    QObject *object = component.create();
+    QVERIFY(object != 0);
+}
+
 void tst_qqmlecmascript::automaticSemicolon()
 {
     QQmlComponent component(&engine, testFileUrl("automaticSemicolon.qml"));